Rear bumper for an automobile



FIG. 1 is a left front perspective view of a rear bumper for an automobile of my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a right side elevational view thereof; and,

FIG. 7 is the left side elevational view thereof. 

The ornamental design for a rear bumper for an automobile, as shown and described. 